Asteroid Psyche (formally designated 16 Psyche) is one of the most intriguing objects in our Solar System’s asteroid belt. Unlike most asteroids composed primarily of rock or ice, Psyche is believed to be largely made of nickel-iron metal, potentially representing the exposed core of an early planetary body whose outer rocky layers were stripped away through violent collisions. With a diameter of about 226 kilometres, it’s among the largest objects in the belt between Mars and Jupiter. Studying it gives us a rare opportunity to “see inside” a planetary core for the first time.
Asteroid 16 Psyche imaged by VLT (Credit : ESO/Vernazza)
Sharing the name of its destination, NASA’s Psyche mission was launched in October 2023 and is scheduled to reach the asteroid Psyche in 2029. On arrival, it will conduct a 26-month orbital investigation; analysing the asteroid’s properties, determine if it truly is an exposed planetary core, analysing its composition and magnetic field, and testing advanced laser communication technology. If the asteroid is indeed an exposed planetary core stripped of its outer layers, then it’s a great opportunity to study such an object without having to drill through hundreds of kilometres of rock.
Everything seemed to be operating according to plan however engineers at NASA are having to investigate a pressure drop in the spacecraft’s propulsion system. The drop seems to be where the xenon gas line feeds its four electric thrusters and it is here that the pressure decreased from 36 psi to about 26 psi on April 1, 2025. This incident, which occurred after the spacecraft began using its solar electric propulsion system in May last year, triggered an automatic safety shutdown of the thrusters. The mission team is now working to identify the cause of the malfunction.
Artist’s illustration of NASA’s Psyche spacecraft (Credit : NASA/JPL-Caltech/Arizona State Univ./Space Systems Loral/Peter Rubin)
The propulsion system, which works by converting solar energy into power that enables the thrusters to expel xenon ions and propel the spacecraft toward its asteroid destination has been temporarily suspended. The mission’s design allows for this pause until at least mid-June without affecting the spacecraft’s trajectory. Engineers are exploring options, including potentially switching to the backup fuel line, as the propulsion system features two identical xenon delivery systems. This contingency measure would allow the mission to resume thrusting while technicians continue to analyse what caused the primary fuel line’s pressure decrease.
Despite this technical setback, NASA remains optimistic about the Psyche mission’s ultimate success. The spacecraft’s robust design, featuring redundant systems and flexible mission parameters, demonstrates the foresight that goes into planning such ambitious deep space endeavours. If engineers successfully diagnose and address the propulsion issue—whether by resolving the primary line’s problem or switching to the backup system—the mission should remain on track to reach its metallic destination in 2029.
Source : NASA’s Psyche Mission Looking Into Propulsion System